This invention relates to a method and an apparatus for machine extracting information from an object that is within a relatively large inspection or interrogation zone.
There are numerous circumstances in which it is desirable to identify information about an object while that object is within or passes through an inspection field or zone. The information can be either affixed to the object such as destination tags on luggage, addresses on letters, or descriptive information on the sides of railroad cars, or the information can relate to the object itself, such as the speed and location of a moving vehicle. If the object or the information on the object has a defined location and orientation with respect to the inspection field or zone, it is generally possible to utilize a machine to read and process the information. If, on the other hand the object's or the information's location and/or orientation is undefined, a manual interface is generally required, or some other provision must be made to somehow locate the object or information within the field. This task is made easier if at least the location and the orientation of the object and any information thereon can be controlled so that its location at a given time is known. If control over the object is impossible, it has generally not been feasible to automate a method or apparatus for locating the object and extracting the information therefrom. This is in part due to the memory capacity that is required for storing and processing the total information contained within a large field in order to locate the object and extract the desired information, as well as the relatively large amount of time that would be involved in doing this.